This application relates to a device for measuring the amount of papermaking stock on a moving fabric or wire during operation of a fourdrinier paper machine.
During the operation of a papermaking machine, it is important to continuously measure the consistency of the pulp and water mixture of the fourdrinier tables. This allows the papermaker to make adjustments to the drainage table. It is important to make these adjustments because in order to obtain a quality paper product the water must drain from the pulp at a certain rate in various sections of the fourdrinier table.
Prior art devices for measuring consistency on a fourdrinier table have serious drawbacks. One such device is an ultrasonic sensing device. This device requires a special supporting beam so it can be placed under the fourdrinier table. However, this beam is so bulky as not to allow measurements to be taken between closely spaced drainage units.
Consistency measurements have also conventionally been made by obtaining blow samples. This involves the stock being blown into a container by compressed air underneath it. The stock can then be measured for consistency. However, this method produces holes in the stock. The paper produced in the area of where the measurements were taken must then be scrapped. Normally, the total machine productivity must be curtailed to allow the series of blow tests. This waste of paper is obviously not economical.